Carlos, Prince of Asturias

Carlos, Prince of Asturias (8 July 1545-24 July 1568) was the eldest son and heir apparent of King Philip II of Spain. He was known to be insane, and his betrothal negotiations with Queen Elizabeth I of England were cancelled after he demanded proof that she was not a man; he died in his father's captivity in 1568.

Biography
Don Carlos was born on 8 July 1545 in Valladolid, Spain, the son of King Philip II of Spain and Maria Manuela of Portugal; his mother died of a hemorrhage four days after giving birth to Carlos. He was delicate and deformed as a child, owing to the Habsburg dynasty's penchant for incest, and he once had a serving girl whipped without reason and enjoyed torturing animals. He was also sickly, falling ill from malaria at the age of 14. In 1560, he was recognized as heir to the Spanish throne under his father, and he was sent to ask for Queen Elizabeth I of England's hand in marriage. While Elizabeth saw him as charming and overly familiar, he demanded proof that she was not secretly a man, ruining the negotiations. In 1562, he fell down a staircase while chasing a servant girl, causing him mental damage. His father passed him over for command of the Spanish forces in the Netherlands with Francisco Alvarez de Toledo, causing Carlos to side with the Dutch rebels in 1565 in an attempt to make himself King. On 17 January 1568, his father had him arrested and imprisoned, and he died, possibly of poisoning, in his jail cell in 1568. His death was used as propaganda by the Dutch Protestants, who then launched the Dutch Revolt.